Underreamer



Marr. 2Q), W23.. J. .i BOOKHQU? AL UNDERREAMER Filed Dec. 2, 1921 5- sheets-sheet l iff/W Man'. 2U, 1923.y 31,449314 J. J. BOOKHOUT ET AL UNDERREAMER Filed Dec. 2, 1921 5 sheefs-sheet. 2

h1-*N T Marr. 20, 1923. 'l Mg J. J. BOOKHOUT ET AL UNDERREAMER Filed Dec. 2, 1921 5 sheets-sheet 5 Illll Illi Patented' lt/ilar. 2li, i123.,

y Ul JOHN'J'. BOQKHOUT AND JS R. ABOOKHCNIJ'EII?, 0E DALLAS, TS.

UNDERRER.

` Application t11ed-1Decemher 3,' 1921'. Serial No. 519,497.

To all whom t mayl concern.

Be it known that we, JOHN J. BooKHoUT' 'and JAMES R. BooKHoU'r, citizens of the United States, residing at Dallas, in the county of Dallas and State of Texas, have invented certain new andy-useful Improvements in Underreamers, of' which the following is a specification. y

This invention relates to new and-useful improvements -in underreamers.

The object of the invention is tot'prov'ide an underreamer having eX-'pandingfcutters arranged to travel over arcuate Aexpanding surfaces which also provide solid supports' for the cutters when expanded. Another feature resides in the arrangement-l whereby the Shanks of the cutters are lirmly seated when said cutters are expanded and,

held against displacement. n i 'Another object of the invention 1s vto provide ample bearing surfaces tor sustaln the upward thrust of the cutters and prevent breakage. A' further object is to produce f an undelreamer which may be connected at its lower end with a suitable drilling tool vso that the two may be used in conjunction and operated in the hole at the same time or either used without withdrawing from the hole to connect the desired tool to the cable. y

An advantage of this tool is that an adequate casing seat isl formed and a rattail or advance hole is drilled, whel'eb danger of setting the casing into the oil sand is obviated. Another advantage is the formation of a straight hole from top to bottom. By drilling and underreaming at the same time, danger of collapsing of the well walls in soft formations is obvia-ted,

because the casing canl be lowered immedi- Fig. `3 is a cross-sectional view taken on 55 the line 3 3 of Fig. 2,

F 1g. tis an enlarged elevation of a portron of the underreamer, the cutters being retraeted, i

5 is a detail showing the stem, 1g. 6 is a similar view at right angles to igs.'7, 8 and 9 are details in elevation of one of the cutters, t F ig. 10 is a plan view of one of the cut- 65 ers,

11 is an underside view of the same,

. F 1g. 12 is a detail in elevation of one cutyter 'expanding and supporting plate,

F 1g. 13 is an elevation of the inner side '70 ofthe same,

Fig. 14 is a cross section on the line 14e-14 of Fig. 12, and Fig. 15 is a vertical section on the line 15-15 of Fig. 12.

ln the drawings the numeral 20 designates a cylindrical stock vor body having a central bore 21 extending downwardly from its upper end. A central stem 22 depends from the lower end of the stock and is preferably integral therewith. rEhe bottom ofl the stock is under cut so as to form an annular inwardly and upwardly inclined socket 23. The outer edge 'of the socket is surrounded by a radial lip 24,. which pro- S5 vides a flat annular bearingsurface and obviates a sharp wedge-shaped edge.

rlhe lower end of the stem is provided with a tapered screw-thread 25 adapted to enter a socket 26 in a coupling 27. rlhe @il upper end of the coupling is formed into an upwardly and outwardly inclined annular seat 28. Between the socket 23 and the seat 28 a pair of segmenta-lplates 29 are enn gaged, their ends being shaped to t the said socketv and seat. 'lhe upper end olB each plate has a marginal shoulder 30 engaging the flat .lip R24. These `plates fit snugly around the stem and have their vertical edges in contact. By screwing the loo coupling onto the stem the plates are firmly fastened inl place.

Below the lip 24.- the stem has a transverse slot 3l and a reduced bore 32 extends from the upper end of the slot to the bore 2l. A' mandrel 33 is mounted to slide snugly in the bore 32 and projects into the slot 31 and the bore 2l. A coiled spring 34 surroundl ing the mandrel rests on the shoulderat-the y bottom of the bores 21 and engages under a head 35 on the upper end ofthe mandrel, whereby said mandrel fis resiliently supported. Y

Each plate 29 has in its outer side a recess provided with an outwardly and upwardly extending curved face 36, presenting a broad bearing -surface transversely of the which' a downwardly inclined ledge 39 explate.v At the upper end of each face, is an overhanging radial shoulder 37 and each face at its lower end terminates at a transverse groove 38 from the lower edge of tends. In theupper central portion of each face 36 a vertical slot 40 is formed and yis extended inwardly thru the shoulder 137.` This gives each slot an upwardly and inwardly inclined outer wall 41 with a shoulder 42, at its upper end, as is best shown in Fig. `15. f

A segmental cutter blade 43 has an arcuate outer face provided with an extended cutter 44 at itsl lower edge. yThis cutter is illustrated in detail in Figs. 7 to 11 incluslve. tending upwardly from its upperv rear por'- tion and also has a curvilinear inner face 44 'conforming to the radius of the face 36 .of each plate 29. Each cutter has its outer face cut back, whereby the cutter lis reduced in thickness upwardly; and also whereby a riding surface for engagement with the wall` of the casing isv provided when the cutter is moved down into the groove and withdrawn as is shown in Fig. 4. l

Each shank .45 has a reduced inwardly extending lug 46 at its upper end of such width as to fit snugly in the slot' 31. The mandrel has a cross bar- 47 at its 'lower end engaging on each side under one of the lugs 46. The mandrel has notches immediately above the bar lfor receiving the lugs (Fig. 2). The stem 22 has curved guides 48 into which the slot 31 opens. The inner verticalfaces of the shanks ride in the guides, while.

the curvilinear faces 44 ride on the faces 36. The -stock 21 has a ythreaded tapered pin 49 at its upper end whereby it may be connected with a'sub or the like for suspension.

at the end of a cable. A transverse-slot 5,0 extends thru'the stock at the .upper end of the bore 21. A wedge tool 51 (Fig. 6) in- "l serted in said slot engages the head35 and forcs the mandrel downwardly, thus compresslng the spring 34. When the mandrelis depressed the cross'bar 47 is lowered, thus permitting the, Shanks 45 to ride down the. guides 48, whereby the cutters 43 are lowered and retracted into the groove 3 8.

The underreamer-is inserted in the upper end of the casing (not shown) and the-tool 51, withdrawn. The spring tends t0 displace the mandrel upwardly whereby the upper portions of the cutters engage the wall The cutter has a central shank 45 exof the casing and ride down the same when the device is lowered into the well. A suitable ldrilling tool (not shown) may be attached to the lower end of the coupling 27 and lowered into the well in advance of the underreamer. When the" hole has been drilled below the casing or the casing is raised, the cutters 43 rideout of the lower end of the casing and are free to expand.-

The spring .34 being released elevates the -mandrel and the cross bar 47 carries the lugs 46 upwardly. When the lugs are carparted to the cutters will be sustainedby the shoulders 37 and 42. rllhe Shanks will also lity snugly between the' inner walls of -the guides 48 and the walls 41 of the slots as well as the side walls of said elements,

whereby said Shanks will be held against lat-4 I eral, radial and upward displacement. The faces 44 will also have an ample bearing on the faces 36, so as to resist any crushing strain to which the 'cutters may be subjected. It is pointed out that amplified bearing surfaces are had for the cuttersand their Shanks and these will be amply supported in both their retracted and extended positions y as well as` during the movement therebe` tween. When the cutters are forced downwardly any 'mud or foreign matter will be 'readily dislodged owing to the inclined ledges 39. y What we claim 1. In an underreamer, a stock, a stem depending from the stock, a spring pressed mandrel inthe stem, supporting elements surrounding the stem and having curved faces, said elements having 'slots in said,l

faces, and cutters havin inner faces riding on `the curved faces an engaging with the mandrel thru the slots of the said elements.

2, In an underreamer, a stock, a stem de'- pending from the stock, a spring pressed mandrel in the stem, supporting elements surrounding the stem and having curved faces, said elements having slots in said faces, cutters having inner faces riding on the curved faces and engaging with the" mandrel thru the slots of the said elements. and a ,drill connecting coupling mounted on the lower end lof the stem.

3. V In an uuderreamer, a stock, a stem depending from the stock and having a slot.. segmental plates mounted on the stem and having curved faces, said plates having slots, guideways in the stem, afmandrel mounted to slide vertically in the stem and stock, and cutters having surfaces contacting with the curvedl faces of the plates and provided with Shanks extending thru the slotsof the plates and stem and engaging the mandrel, said cutter shanks riding in the guideways of the stem.

4. In an underreamer, a stock, a stem depending from -the stock and having a slot, segmental plates mounted on the stem and having curved faces, said plates having slots, guideways in the stem,.a mandrel mounted to slide vertically inl the stem and stock, cutters having surfaces contacting with the curved faces of the plates the plates.

and provided with Shanks extending thru the slots of the plates and stem and engaging the mandrel, said cutter shanks riding in the guideways of the stem, anda drill coupling mounted on the stem and supporting 5. In an underreamer, a stock, a stem depending from the stock, an annular support surrounding the stem and having curved cutter expanding faces, curved guideways on the stem, cutters having curvilinear faces in constant engagement with the expanding faces at all adjustments of said cutters, shanks carried by the cutters and in constant engagement with the guidexvaysrand a spring pressed mandrel for elevating the cutters. l

. 6. In an underreamer, a stock, a stem depending from the stock, an under cut annular socket in the lower end of the stock surrounding the stem, a drill coupling mounted on the lower end of the stem and having a downwardly inclined seat, segmental plates surrounding the stem and A,having oppositely beveled ends engaging in the socket and the seat, whereby said plates are' fastened against movement, said plates having recesses provided with upwardly curved cutter expanding faces, cutters mounted to yslide vertically in said recesses and having faces engaging said expanding faces, and a resiliently sustained mandrel mounted in the stock and stem and engaged by the cutters.

7. In an underreamer, a stock, a stem depending from the stock and having a transverse slot, a spring sustained mandrel mounted to slide in the stock and stem and projecting into the slot of the stem, a pair of segmental plates surrounding'the stem and having recesses provided withcurved expanding faces, said plates having slots regis tering with the slot of the stem 'and'extendingl above the recesses, said stem having vertical guides, and cutters having curvilinear faces engaging the expanding faces in the recesses and provided with Shanks extendingv thru the slots of the platesv and the stem' and engaging the mandrel the plates having shoulders'engaged by the cutter and their Shanks to sustain the upward thrust imparted to the cutters. N

8. In an underreamer, ya stock, a stem depending from the stock and having' a transverse slot, a spring sustained mandrel mounted to slide in the stock and stem and of segmental plates surrounding the stem and havmg recesses provided with curved expanding faces, said plates having slots registering with the slot of the stem and extending above the recesses, said stem having vertical guides, cutters having curvilinear faces engaging the expanding faces in the recesses and provided with shanks extend.

JUHN J). BOOKHOUT. JAMES R. BOOKHUUI.

projecting into the slot of the stem, a pair 

